This invention relates to a reservoir for drinks dispensing machines.
Many drinks dispensing machines available in the market, such as automatic coffee or tea making machines, contain reservoirs for various liquids and drinks, e.g. integrated milk containers heat storing containers for ready-to-dispense drinks, or water containers for preparing drinks, from which liquid quantities which have a constant predetermined volume are to be tapped, either to fill a predetermined portion container, such as a cup or a pot, with a drink, or to take off a predetermined amount of water for preparing a predetermined amount of drink, or to take off a predetermined amount of milk for mixing it with a predetermined amount of coffee or tea or for foaming up for the preparation of cappuccino. In all these cases it is necessary that the predetermined volume of liquid is substantially constant during each tapping process, no matter how high the liquid level is in the reservoir. A high liquid level in the reservoir for instance during discharge by gravity or by a time-controlled valve will lead to a slightly increased discharge quantity compared to the discharge quantity which exits at the same valve opening time but at a lower filling level in the reservoir. At present, this is managed in that either a constant overpressure is generated in the reservoir above the liquid level or in that the filling level in the reservoir is detected by probes and the time control is varied accordingly. Both measures are relatively complicated.
The object of the invention is to provide a reservoir by means of which a level compensation can be obtained in a simple constructive way.
By the substantially air-tight closure of the reservoir body, an increasing vacuum will build up above the liquid level when liquid is taken from the container body, said vacuum counteracting the weight of the liquid column in the reservoir body. There will be a balance between the external pressure applying at the ventilation opening and the vacuum in the container body above the liquid level, wherein air drops in from the ventilation opening as soon as the vacuum in the reservoir body drops by a predetermined value below the external pressure. This balance does not depend on the height of the liquid column in the reservoir body, so that an appropriate compensation of the weight of the liquid column is achieved at any height of the liquid column in the reservoir body.
In stationary reservoirs, i.e., reservoirs that cannot be tilted for being filled, the measure according to the invention is sensible.
There are different preferred arrangements of the ventilation opening.
It is ensured that the air bubbles dropping in do not become too large.
There is ensured a complete emptyability of the reservoir.
The embodiments of the output line are the simplest possibility in terms of construction, since a further passage to the reservoir to be sealed is not required.
The present invention facilitates filling the reservoir body.